This book constitutes the refereed proceedings of the 21st International Conference on Modeling Decisions for Artificial Intelligence, MDAI 2024, held in Umeå, Sweden, during August 27-30, 2024.The 18 full papers were carefully reviewed and selected from 37 submissions. and data science and data privacy.

Invited paper.- Taste Media Innovative Technology Transforms the Eating Experience.- Fuzzy measures and integrals.- An axiomatic definition of non discrete Mbius transform.- Fuzzy Rough Choquet Distances.- Uncertainty in AI.- Entropies from f divergences.- Comparative Study of Methods for Estimating Interval Priority Weights Focusing on the Accuracy in Selecting the Best Alternative.- Clustering.- Sequential Cluster Extraction by Noise Clustering Based on Local Outlier Factor.- On Objective Based Clustering from the Perspective of Transportation Problem.- Data science and data privacy.- Decision Tree Based Inference of Lightning Network Client Implementations.- nuggets Data Pattern Extraction Framework in R.- User centred Argumentation Analysis of Local Explanations in Explainable AI.- Revised Margin-Maximization Method for Fuzzy Nearest Prototype Classification.- Bistochastically private release of data streams with delay.- Differentially Private Extreme Learning Machine.- Studying the impact of edge privacy on link prediction in temporal graphs.- Dissimilar Similarities Comparing Human and Statistical Similarity Evaluation in Medical AI.- On the necessity of counterfeits and deletions for continuous data publishing.- A Poisoning-Resilient LDP schema leveraging Oblivious Transfer with the Hadamard Transform.- Experimental Evaluation for Risk Assessment of Privacy Preserving Synthetic Data.- Transforming Stock Price Forecasting Deep Learning Architectures and Strategic Feature Engineering.